Two important advantages of iterative reconstruction (IR) algorithms over standard filtered backprojection (FBP) are improved resolution and better noise performance. IR algorithms thereby allow the use of patient dose that is lower than previously required with the use of standard FBP.
IR algorithms are separated into two general categories. A first category includes system optics models, commonly referred to as model-based IR (MBIR) while a second category fails to include system optics models. MBIR algorithms theoretically further improve the performance of prior art IR algorithms since errors and statistics are substantially corrected. One source of the errors is originated from system optics. MBIR algorithms further include a system optics model (SOM) to some extent in prior art. Thus, it is desired to improve the use of SOM in MBIR to reconstruct a CT image with good resolution and noise performance from data acquired at a low dose level.